Conventionally, when a optician's store receives an order of a spectacle wearer, the spectacle lens is determined on the basis of the wearer's prescription and the shape and size of a spectacle frame to be used. The lens is machined on the basis of the prescription, lens information, and spectacle frame shape information. The machined spectacle lens is fitted in the lens frame of the spectacle frame.
Recently, however, as disclosed in, e.g., Japanese Patent Nos. 2982991 and 3548569, Japanese Patent Laid-Open No. 4-13539, and the like, a spectacle lens supply system or machining system is becoming popular not only in Japan but also overseas. According to this system, the optician's store and lens machining factory cooperate with each other. The optician's store practices optometry, writes a prescription, asks the factory to do spectacle lens edging. The optician's store receives the finished spectacle lens and fits it in the spectacle frame.
Spectacle lens edging at the factory includes edging of cutting a round uncut spectacle lens in accordance with the lens frame shape of the spectacle frame and beveling of forming a V-shaped projection (bevel) on the edge face of the edged spectacle lens.
In the following description of the present invention, the frame-like portions to which the spectacle lenses of spectacles are to be fitted will be referred to as a lens frame. The remaining portion of the spectacles excluding the spectacle lenses, that is, a portion comprising the pair of left and right lens frames, a bridge that connects the lens frames, and a pair of left and right temples connected to the lens frames through end pieces will be referred to as a spectacle frame.
In lens machining at the factory, the lens is machined without the spectacle frame at hand. It is thus important to grasp the accurate shape data on the spectacle frame. For this purpose, from the optician's store the factory side receives information necessary for fitting the lens in the frame including spectacle lens information, spectacle frame information including lens frame shape information, prescription values, and layout information, and performs a necessary calculation process on the basis of the received information, thus generating machining information used for machining the spectacle lens. A machining device machines the spectacle lens on the basis of the machining information.
The lens frame shape information on the spectacle frame includes three-dimensional measurement data R, θ, and Z, a circumference, the tilt of the lens frame, a frame PD, and the like. R represents the radial displacement of the measurement unit (to be also referred to as a stylus hereinafter) of a three-dimensional spectacle frame shape measurement device within a horizontal plane, θ represents the rotational displacement of the stylus within the horizontal plane, and Z represents the displacement of the stylus in the direction of height (vertical direction).
Concerning the process of the spectacle frame information including the lens frame shape information, for example, the spectacle lens supply system described in Japanese Patent No. 3548569 described above discloses the process of more accurate lens frame information such as the circumference of the inner circumferential surface of the lens frame, the face form angle, and the like. Japanese Patent Laid-Open No. 4-13539 discloses a central machining system in a large-scale spectacle chain store. The central machining system is based on the consideration of a change of the order content and re-machining of the manufacture, and discloses spectacle frame shape measurement and correction of a machine error in an edging device.